The present invention relates to a hermetic reciprocating compressor.
A hermetic reciprocating compressor is generally employed in a cooling system such as a refrigerator or an air conditioner, so as to compress a gaseous refrigerant from an evaporator to a high temperature and high-pressure state and supply the compressed refrigerant to a condenser.
FIG. 4 shows a sectional view of a conventional hermetic reciprocating compressor. As shown in FIG. 4, the conventional compressor includes a casing 51 forming a closed internal space, a cylinder apparatus for receiving, compressing and discharging a refrigerant and a driving motor for driving the cylinder apparatus.
The driving motor includes a stator 52 around which an exciting coil is wound and a rotor 53 having a permanent magnet. The rotor 53 is rotatably installed inside the stator 52. A rotating shaft 54 is fitted into the rotor 53 and rotates therewith.
A journal 54a is formed at the lower portion of the rotating shaft 54 and rotatably supported by a bearing 55. An eccentric portion 54b is formed at the lower end portion of the journal 54a and an oil pickup tribe 60 is extended downwardly front the eccentric portion 54b. The oil pickup tube 60 picks tip a lubricating oil contained in an oil container 61 provided at the bottom of the casing 51 and supplies the oil between the journal 54a and the bearing 55 when the rotating shaft 54 rotates. A spiral oil groove 62 is formed on the surface of the journal 54a of the rotating shaft 54 to facilitate the upward flow of the oil.
The cylinder apparatus has a cylinder 56a which is provided at a cylinder block 56 for supporting the driving motor and a piston 57 which reciprocates inside the cylinder 56a. The bearing 55 is installed on the cylinder block 56. The piston 57 is connected to the eccentric portion 54b of the rotating shaft 54 via a connecting rod 58, to thereby convert the rotational movement of the rotating shaft 54 into the reciprocating movement of the piston 57.
FIG. 5 shows a plan viewed of the conventional bearing 55. As shown in FIGS. 4 and 5, the bearing 55 has a cylindrical bearing body 67 for rotatably supporting the journal 54a of the rotating shaft 54 and a flange 68 formed at a lower portion of the bearing body 67. The flange 68 is installed on the cylinder block 56 by a bolting structure. A plurality of holes 66 are formed at the flange 68 to receive bolts (not shown) for the bolting structure.+ An oil discharging groove 63 is formed at an upper portion of the rotating shaft 54 to discharge the oil moving upward from between the rotating shaft 54 and the journal 54a. The lubricating oil discharging through the oil discharging groove 63 flows downward alone the outer stirface of the bearing 55, is collected on the cylinder block 56 and then overflows from the cylinder block 56 into the oil container 61.
However, the oil which is collected on the cylinder block 56 is boiled by the cylinder 56 block which is heated to a high temperature during the compressing process of the refrigerant. The boiling of the oil generates noises and deteriorates characteristics of the oil.